1. Field of the Invention
The present invention generally relates to a wireless mobile communication system, and in particular, to a network entry method in a wireless mobile communication system.
2. Description of the Related Art
Generally, a Mobile Station (MS) has to perform a network entry operation to communicate with a Base Station (BS) in a wireless mobile communication system.
FIG. 1 is a signaling diagram illustrating a network entry procedure between a BS 150 and an MS 100 in a conventional wireless mobile communication system.
Referring to FIG. 1, the MS 100 receives an UpLink-map (UL-MAP) message and a DownLink-map (DL-MAP) message from the BS 150 in step 102 and receives an Uplink Channel Description (UCD) message and a Downlink Channel Description (DCD) message in step 104, thereby acquiring synchronization with the BS 150. The DL-MAP message and the UL-MAP message are usually used in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system or an Institute of Electrical and Electronics Engineers (IEEE) 802.16 communication system, which is a wideband wireless access communication system. Therefore, in the following description, the OFDMA communication system or the IEEE 802.16 communication system will be taken as an example.
The MS 100 sends a ranging code for initial ranging to the BS 150 in step 106. The ranging code is used to adjust link timing and power offset. Upon completion of timing and offset adjustment, the BS 150 sends a ranging response (RNG-RSP) message having a status field marked as ‘success’ to the MS 100 in step 108.
The MS 100 sends a ranging request (RNG-REQ) message to the BS 150 in step 112. The RNG-REQ message includes a Medium Access Control (MAC) address of the MS 100. The BS 150, having received the RNG-REQ message, allocates a basic Connection Identifier (CID) and a primary CID of the MS 100 based on the MAC address and sends an RNG-RSP message including the basic CID and the primary CID to the MS 100 in step 114.
The MS 100 having received the RNG-RSP message sends a Subscriber Station Basic Capability Negotiation Request (SBC-REQ) message to the BS 150 in step 122. The SBC-REQ message, a MAC message for basic capability negotiation, includes a physical layer parameter and security negotiation support information that can be provided by the MS 100. The BS 150 receives the SBC-REQ message and checks information such as the physical layer parameter and the security negotiation support included in the SBC-REQ message. Then the BS 150 sends a Subscriber Station Basic Capability Negotiation Response (SBC-RSP) message to the MS 100 in response to the SBC-REQ message in step 124.
The MS 100 sends a Privacy Key Management Request (PKM-REQ) message to the BS 150 in step 132. The PKM-REQ message, a MAC message for MS authorization, includes a unique certificate of the MS 100. Upon receiving the PKM-REQ message, the BS 150 performs authorization on the MS 100 with an Authorization Server (AS, not shown) using the unique certificate of the MS 100, included in the PKM-REQ message. The BS 150 sends a Privacy Key Management Response (PKM-RSP) message including the authorization result to the MS 100 in step 134. The PKM-RSP message includes an Authorization Key (AK) and a Traffic Encryption Key (TEK) that are allocated to the MS 100 when the MS 100 is an authorized MS.
The MS 100 having undergone authorization sends a Registration Request (REG-REQ) message to the BS 150 in step 142. The REG-REQ message includes registration information of the MS 100. The BS 150 detects the registration information included in the REG-REQ message, registers the MS 100 therein according to the detection result, and allocates a secondary management CID for the MS 100. The BS 150 sends a Registration Response (REQ-RSP) message including the secondary management CID to the MS 100 in step 144.
Although not shown in FIG. 1, the MS 100 then performs an Internet Protocol (IP) connection and service flow connection procedure with the BS 150.
FIG. 2 illustrates a MAC address format used in a conventional wireless mobile communication system.
Referring to FIG. 2, a MAC address has a 48-bit physical address format. In the MAC address, an upper 24 bits 202 indicate a company ID (or manufacturer ID) administered by the Institute of Electrical and Electronics Engineers (IEEE) standard and a lower 24 bits 204 indicate a serial number or ID assigned to each terminal by a manufacturer.
As discussed above, an MS in a wireless mobile communication system performs various processes with a BS for initial network entry. As a result, a large amount of signaling is generated between the MS and the BS, which causes a delay in the network entry process. Moreover, when a plurality of MSs attempt network entry, a BS experiences heavy load in processing signaling generated by the MSs, increasing the delay in the network entry process.